Redfin, the online real estate brokerage based in Seattle, has raised $14.8 million this venture round, led by new investor Globespan Capital Partners. That brings the virtual brokerage’s total financing to roughly $46 million.

The company plans to use the funding from this round for research and development and expansion into new markets, as it currently operates in fewer than 20 cities, including Chicago, Dallas and Atlanta.

Other participating investors this round included Madrona Venture Group, Vulcan Capital, Draper Fisher Jurvetson and Greylock Partners, all of which have invested in Redfin previously. Globespan’s managing director Venky Ganesan will join Redfin’s board as part of the investment deal.

The Redfin business model differs from that of Zillow, another Seattle-based online real estate company. While Zillow earns money from advertising, subscriptions and per-click fees charged to lenders (which, interestingly enough, is shared with Redfin when their customers shop for mortgages at Zillow), Redfin makes a commission on home sales and agent referral fees.

Since its launch in 2006, Redfin users have purchased or sold over $6 billion in homes, saving them an average of $7,000 per transaction.

Although Zillow went public earlier this year, Redfin is not currently undertaking an IPO.